High-temperature gas cooled reactor steam bypass system and control method

Abstract

The invention relates to the technical field of nuclear power, in particular to a high-temperature gas cooled reactor steam bypass system and a control method. A steam bypass system of a high-temperature gas cooled reactor comprises a condenser, a first condenser and a second condenser, one end of the first branch is connected and suitable for being communicated with a steam outlet of a main steam pipeline, steam flows in the main steam pipeline, the other end of the first branch is connected with a first condensed gas inlet, and a first bypass valve is arranged on the first branch; one end of the first pressure maintaining mechanism is communicated with the first bypass valve, and the other end of the first pressure maintaining mechanism is suitable for being communicated with a turboset. The method solves the problems that in the shutdown process due to the fact that a turbine of the high-temperature gas cooled reactor breaks down, if steam dredging cannot be conducted in time, a reactor protection action can be caused, unplanned shutdown of the reactor is caused, and the operation benefits of a power station are reduced.

Description

Technical Field

[0001] The present invention relates to the field of nuclear power technology, and in particular to a high temperature gas-cooled reactor steam bypass system and a control method. Background Art

[0002] The high-temperature gas-cooled reactor demonstration project adopts a mode of two reactors driving one steam turbine. When the unit is running at full power, the two reactors generate about 500MW of thermal power, which is used to generate superheated steam through heat transfer through the steam generator, driving the steam turbine to generate about 211MW of electrical power.

[0003] Under normal operating conditions, the two reactors of the high-temperature gas-cooled reactor nuclear power unit operate at the same time, and the steam turbine is connected to the grid. However, when the steam turbine load rejection condition occurs, the steam turbine will be shut down or disconnected unplanned. At this time, the steam generated by the reactor cannot continue to enter the steam turbine to do work, and needs to enter the condenser through the steam bypass system for condensation to form a closed loop of steam and water to ensure the normal operation of the reactor.

[0004] Since the primary circuit of the high-temperature gas-cooled reactor is equipped with protection signals such as the helium-to-water flow ratio and the negative change rate of helium pressure, if the steam turbine fails and is shut down, if there is no timely response to steam diversion, the reactor protection will be activated, resulting in an unplanned shutdown of the reactor, reducing the operating efficiency of the power plant and even causing damage to equipment, increasing the maintenance cost of the power plant. Summary of the invention

[0005] In view of this, the present invention provides a high-temperature gas-cooled reactor steam bypass system and control method to solve the problem that when a high-temperature gas-cooled reactor is shut down due to a failure of a steam turbine, if the steam is not promptly responded to and steam is diverted, the reactor protection will be activated, resulting in an unplanned shutdown of the reactor, reducing the operating efficiency of the power plant and even causing damage to equipment, thereby increasing the maintenance cost of the power plant.

[0006] In a first aspect, the present invention provides a high temperature gas-cooled reactor steam bypass system, comprising:

[0007] A condenser, wherein the condenser is provided with a first condensed gas inlet;

[0008] a first branch, one end of which is connected to the steam outlet of a main steam pipeline, in which steam flows, and the other end of which is connected to a first condensate inlet, and a first bypass valve is provided on the first branch;

[0009] A first pressure maintaining mechanism, wherein one end of the first pressure maintaining mechanism is communicated with the first bypass valve, and the other end of the first pressure maintaining mechanism is suitable for communicating with the steam turbine unit.

[0010] By setting the first branch, the first bypass valve and the first pressure maintaining mechanism, the first pressure maintaining mechanism and the first bypass valve cooperate to control the opening and closing of the first branch, so that when the steam pressure in the main steam pipeline increases suddenly, the first bypass valve is opened through the first pressure maintaining mechanism, so that part of the steam enters the condenser, thereby quickly reducing the steam pressure in the main steam pipeline, responding in time to steam diversion, so that the steam pressure in the main steam pipeline is maintained within a safe range, and realizing rapid control of steam pressure. In the face of the sudden increase in steam pressure in the main steam pipeline, steam diversion can be responded to in time to keep the steam pressure in the main steam pipeline within a normal range, avoiding the protection action of the reactor, and preventing unplanned shutdown of the reactor, ensuring the operating efficiency of the power plant and reducing additional maintenance costs.

[0011] In an optional embodiment, the first hydraulic station and the first fluid circuit are further included, the first pressure maintaining mechanism is provided with a hydraulic chamber, and one end of the first fluid circuit is connected to the hydraulic chamber. When the first pressure maintaining mechanism closes the first bypass valve, the pressure in the hydraulic chamber remains normal; when the pressure in the hydraulic chamber is released, the first pressure maintaining mechanism opens the first bypass valve.

[0012] In an optional embodiment, a second fluid circuit is further included, one end of the second fluid circuit is connected to the first hydraulic station, the other end of the second fluid circuit is connected to the steam turbine unit, the steam turbine unit is connected to the condenser pipeline, and the end of the first fluid circuit away from the first pressure maintaining mechanism is arranged on the second fluid circuit between the first hydraulic station and the first bypass valve. When the steam turbine unit fails, the steam turbine unit will cause the oil pressure on the second fluid circuit to drop rapidly, the first fluid circuit is connected to the second fluid circuit, so that the oil pressure on the first fluid circuit is reduced, and then the pressure in the hydraulic chamber of the first pressure maintaining mechanism is reduced.

[0013] In an optional embodiment, a second pressure maintaining mechanism and a main steam valve group are provided on the second fluid circuit, and a second pressure maintaining mechanism and a main steam valve group are provided in sequence from the first hydraulic station toward the steam turbine unit.

[0014] In an optional embodiment, it further includes a one-way check valve, which is arranged on the second fluid circuit and between the second drive mechanism and the first hydraulic station.

[0015] In an optional embodiment, a second branch is further included, one end of the second branch is connected to the first branch, and the other end of the second branch is connected to a second condensed gas inlet of the condenser.

[0016] In an optional embodiment, it further includes a second bypass valve, which is arranged on the second branch.

[0017] In an optional embodiment, it further includes a third pressure maintaining mechanism and a second hydraulic station, one end of the third pressure maintaining mechanism is connected to the second bypass valve, and the other end of the third pressure maintaining mechanism is connected to the second hydraulic station via a third fluid path.

[0018] In an optional embodiment, a controller is further included, and the controller is connected to the first hydraulic station, the second hydraulic station, the steam turbine unit, and the main steam valve unit circuit respectively.

[0019] In a second aspect, the present invention also provides a control method for a steam bypass system of a high temperature gas-cooled reactor, in which, under normal operating conditions, the steam turbine unit operates normally, the first bypass valve is closed by the first pressure maintaining mechanism, and the first bypass valve isolates the first branch; under abnormal conditions, the steam turbine unit fails and shuts down, the pressure in the main steam pipeline increases suddenly, and the first pressure maintaining mechanism opens the first bypass valve, allowing the steam in the main steam pipeline to enter the condenser through the first branch. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 A schematic diagram of a steam bypass system for a high temperature gas-cooled reactor according to an embodiment of the present invention;

[0022] Figure 2 Schematic diagram of a first pressure maintaining mechanism according to an embodiment of the present invention.

[0023] Explanation of the reference numerals in the accompanying drawings: 1. first hydraulic station; 2. main steam pipeline; 3. first pressure maintaining mechanism; 301. hydraulic chamber; 302. piston; 303. quick-opening spring; 304. first liquid inlet; 305. second liquid inlet; 4. first bypass valve; 5. second bypass valve; 6. second hydraulic station; 7. steam turbine unit; 8. condenser; 9. second pressure maintaining mechanism; 10. main steam valve group; 11. one-way check valve; 12. third pressure maintaining mechanism; 13. first branch; 14. second branch; 15. first liquid circuit; 16. second liquid circuit; 17. third liquid circuit. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0025] Combine the following Figure 1 and Figure 2 , describing an embodiment of the present invention.

[0026] According to an embodiment of the present invention, on the one hand, a high-temperature gas-cooled reactor steam bypass system is provided, comprising: a condenser 8, provided with a first condensate inlet; a first branch 13, one end of which is connected and suitable for being connected to the steam outlet of a main steam pipe 2, in which steam flows, the other end of the first branch 13 is connected to the first condensate inlet, and a first bypass valve 4 is provided on the first branch 13; a first pressure maintaining mechanism 3, one end of which is connected to the first bypass valve 4, and the other end of the first pressure maintaining mechanism 3 is suitable for being connected to a steam turbine unit 7.

[0027] In this embodiment, under normal operating conditions, the steam turbine unit 7 operates normally, and the first bypass valve 4 is closed by the first pressure maintaining mechanism 3, and the first bypass valve 4 isolates the first branch 13; under abnormal conditions. The steam turbine unit 7 fails and shuts down, and the pressure in the main steam pipeline 2 increases suddenly. The first pressure maintaining mechanism 3 opens the first bypass valve 4, so that the steam in the main steam pipeline 2 enters the condenser 8 through the first branch 13. By setting the first branch 13, the first bypass valve 4 and the first pressure maintaining mechanism 3, the first pressure maintaining mechanism 3 and the first bypass valve 4 cooperate to control the opening and closing of the first branch 13, so that when the steam pressure in the main steam pipeline 2 increases suddenly, the first bypass valve 4 is opened, so that part of the steam enters the condenser 8, thereby reducing the steam pressure in the main steam pipeline 2, so that the steam pressure in the main steam pipeline 2 is maintained within a safe range, and the steam pressure is quickly controlled. It should be noted that the steam pressure in the main steam pipeline 2 is in a high pressure state.

[0028] like Figure 1 As shown, in one embodiment, it further includes a first hydraulic station 1 and a first fluid circuit 15 , the first pressure maintaining mechanism 3 is provided with a hydraulic chamber 301 , and one end of the first fluid circuit 15 is in communication with the hydraulic chamber 301 .

[0029] In this embodiment, when the first pressure maintaining mechanism 3 closes the first bypass valve 4, the pressure in the hydraulic chamber 301 remains normal; when the pressure in the hydraulic chamber 301 is released, the first pressure maintaining mechanism 3 opens the first bypass valve 4. It should be noted that the liquid in the hydraulic chamber 301 in the first pressure maintaining mechanism 3 is hydraulic oil, and the liquid in the first hydraulic station 1 is hydraulic oil. It should be noted that the first pressure maintaining mechanism 3 includes a cylinder body, which is double-sided oil inlet and has a quick-opening spring 303, that is, the lower part of the piston 302 is the first liquid inlet 304, and the upper part is the second liquid inlet 305. The quick-opening spring 303 is arranged at the lower part of the piston 302. Under normal pressure, the quick-opening spring 303 is pressurized to close the first bypass valve 4. When the oil pressure is lost, the quick-opening spring 303 opens the first bypass valve 4 upward.

[0030] like Figure 1 As shown, in one embodiment, it also includes a second liquid circuit 16, one end of the second liquid circuit 16 is connected to the first hydraulic station 1, the other end of the second liquid circuit 16 is connected to the turbine unit 7, the turbine unit 7 is connected to the condenser 8 pipeline, and the end of the first liquid circuit 15 away from the first pressure maintaining mechanism 3 is arranged on the second liquid circuit 16 between the first hydraulic station 1 and the first bypass valve 4.

[0031] In this embodiment, when the turbine unit 7 fails, the turbine unit 7 will cause the oil pressure on the second liquid circuit 16 to drop rapidly, and the first liquid circuit 15 is connected to the second liquid circuit 16, thereby reducing the oil pressure on the first liquid circuit 15, thereby causing the pressure in the hydraulic chamber 301 of the first pressure maintaining mechanism 3 to drop.

[0032] like Figure 1 As shown, in one embodiment, the second fluid circuit 16 is provided with a second pressure maintaining mechanism 9 and a main steam valve group 10, and the second pressure maintaining mechanism 9 and the main steam valve group 10 are sequentially provided from the first hydraulic station 1 toward the steam turbine group 7. The pressure in the second fluid circuit 16 is controlled by the cooperation of the second pressure maintaining mechanism 9 and the main steam valve group 10. It should be noted that the main steam valve group 10 contains hydraulic oil for controlling the steam turbine group 7, and the hydraulic oil of the main steam valve group 10 is connected to the second fluid circuit 16. In this embodiment, the second pressure maintaining structure 9 is not specifically limited, and it can be a hydraulic cylinder, etc., as long as it plays a role in maintaining pressure.

[0033] like Figure 1As shown, in one embodiment, a one-way check valve 11 is further included, and the one-way check valve 11 is arranged on the second liquid circuit 16, and the one-way check valve 11 is arranged between the second drive mechanism and the first hydraulic station 1. The one-way check valve 11 allows the liquid in the second liquid circuit 16 to flow from the first hydraulic station 1 to the steam turbine unit 7, but cannot flow from the steam turbine unit 7 to the first hydraulic station 1, thereby realizing one-way flow of the second liquid circuit 16. When the steam turbine unit 7 operates normally and the liquid loses pressure in the first pressure control mechanism, the second pressure maintaining mechanism 9 will not lose pressure.

[0034] like Figure 1 As shown, in one embodiment, it also includes a second branch 14, one end of the second branch 14 is connected to the first branch 13, the other end of the second branch 14 is connected to the second condensed gas inlet of the condenser 8, and a second bypass valve 5 is arranged on the second branch 14.

[0035] In this embodiment, a first branch 13 and a second branch 14 are provided. When a problem occurs in the first branch 13 and a failure occurs in the steam turbine unit 7, the steam pressure in the main steam pipeline 2 is controlled by the second branch 14. It should be noted that the connection between the second branch 14 and the first branch 13 is located between the main steam pipeline 2 and the first bypass valve 4, so as to achieve the effect of directly connecting the second branch 14 to the main steam pipeline 2.

[0036] like Figure 1 As shown, in one embodiment, it also includes a third pressure maintaining mechanism 12 and a second hydraulic station 6, one end of the third pressure maintaining mechanism 12 is connected to the second bypass valve 5, and the other end of the third pressure maintaining mechanism 12 is connected to the second hydraulic station 6 through a third fluid path 17.

[0037] In this embodiment, when the first branch 13 cannot be opened, the third pressure maintaining mechanism 12 and the second bypass valve 5 control the opening and closing of the second branch 14; when the first branch 13 can be opened, the second hydraulic station 6 cooperates with the third pressure maintaining mechanism 12 to control the opening degree of the second bypass valve 5 and fine-tune the pressure in the main steam pipeline 2. It should be noted that the third pressure maintaining mechanism 12 has the same structure as the first pressure maintaining mechanism 3, and the third pressure maintaining mechanism 12 is provided with a hydraulic chamber 301. It should be noted that the liquids in the hydraulic chambers 301 of the second hydraulic station 6 and the third pressure maintaining mechanism 12 are hydraulic oil.

[0038] In one embodiment, a controller is further included, and the controller is respectively connected to the first hydraulic station 1, the second hydraulic station 6, the steam turbine unit 7, and the main steam valve unit 10 to achieve automatic control.

[0039] According to an embodiment of the present invention, on the other hand, a control method for a high temperature gas-cooled reactor steam bypass system is provided, comprising the following steps:

[0040] 1) When the steam turbine unit 7 operates normally, the first pressure maintaining mechanism 3, the second pressure maintaining mechanism 9 and the third pressure maintaining mechanism 12 maintain the pressure, so that the first bypass valve 4 and the second bypass valve 5 remain in the closed state, ensuring that the steam pressure in the main steam pipeline 2 is stable;

[0041] 2) When the steam turbine unit 7 fails, the steam pressure in the main steam pipeline 2 increases suddenly. The controller receives the pressure signal in the main steam pipeline 2, and controls the first hydraulic station 1. The main steam valve group 10 of the second liquid circuit 16 releases pressure due to the failure of the steam turbine unit 7. The hydraulic pressure of the entire second liquid circuit 16 and the first liquid circuit 15 is reduced, and the hydraulic pressure in the hydraulic chamber 301 of the first pressure maintaining mechanism 3 is reduced, so that the first bypass valve 4 is opened, and a part of the steam flows out of the steam outlet of the main steam pipeline 2 through the first branch 13 into the condenser 8. At the same time, the controller controls the second hydraulic station 6 to reduce the pressure in the third liquid circuit 17 through the second hydraulic station 6, and controls the opening degree of the second bypass valve 5 to further fine-tune the steam pressure in the main steam pipeline 2;

[0042] 3) When the turbine unit 7 fails and the first branch 13 fails, the controller controls the second hydraulic station 6 to reduce the pressure in the third hydraulic circuit 17 through the second hydraulic station 6, and fully opens the second bypass valve 5, so that the steam in the main steam pipeline 2 enters the condenser 8 through the second branch 14, so that the steam pressure in the main steam pipeline 2 remains stable;

[0043] 4) When the steam turbine unit 7 operates normally, the second pressure maintaining mechanism 9 suddenly loses pressure, and the controller starts the first hydraulic station 1 to make the first hydraulic station 1 maintain the pressure in the second liquid circuit 16 stable, so as to ensure the pressure in the first liquid circuit 15 is stable and ensure that the first bypass valve 4 is in a closed state.

[0044] The high-temperature gas-cooled reactor steam bypass system provided by the present invention has the following advantages: (1) the response capability of the first branch 13 and the second branch 14 under transient operating conditions such as load shedding of the steam turbine is improved, the steam pressure of the main steam pipe 2 can be reduced in time, the normal operation of the reactor is ensured, the reactor will not be shut down or equipment will not be damaged due to accidents, and the maintenance cost is reduced; (2) by providing the first branch 13 with the first bypass valve 4 and the second branch 14 with the second bypass valve 5, the rapid control of the steam pressure of the main steam pipe 2 is improved, and the accuracy of pressure control can also be improved; (3) by connecting the hydraulic oil of the main steam valve group 10 used by the steam turbine unit 7 with the hydraulic oil of the first bypass valve 4, the joint control capability of the steam turbine unit 7 and the first bypass valve 4 is improved; (4) the first branch 13 and the second branch 14 are provided, the redundancy and reliability of the bypass system are improved, and the system unavailability caused by a single branch failure is prevented.

[0045] As an alternative implementation, the hydraulic oil in the present application may also be replaced by water.

[0046] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A high temperature gas-cooled reactor steam bypass system, characterized in that: include: A condenser (8), wherein the condenser (8) is provided with a first condensed gas inlet; a first branch (13), one end of the first branch (13) being connected to the steam outlet of the main steam pipeline (2), steam flowing in the main steam pipeline (2), the other end of the first branch (13) being connected to the first condensate inlet, and a first bypass valve (4) being provided on the first branch (13); A first pressure maintaining mechanism (3), one end of which is in communication with a first bypass valve (4), and the other end of which is suitable for communicating with a steam turbine unit (7).

2. The high temperature gas-cooled reactor steam bypass system according to claim 1, characterized in that: It also includes a first hydraulic station (1) and a first fluid circuit (15); the first pressure maintaining mechanism (3) is provided with a hydraulic chamber (301); one end of the first fluid circuit (15) is in communication with the hydraulic chamber (301).

3. The high temperature gas-cooled reactor steam bypass system according to claim 2, characterized in that: The invention also comprises a second liquid circuit (16), one end of which is connected to the first hydraulic station (1), the other end of which is connected to the steam turbine unit (7), the steam turbine unit (7) being connected to a condenser (8) pipeline, and the end of the first liquid circuit (15) facing away from the first pressure maintaining mechanism (3) being arranged on the second liquid circuit (16) between the first hydraulic station (1) and the first bypass valve (4).

4. The high temperature gas-cooled reactor steam bypass system according to claim 3, characterized in that: The second fluid circuit (16) is provided with a second pressure maintaining mechanism (9) and a main steam valve group (10), and the second pressure maintaining mechanism (9) and the main steam valve group (10) are provided in sequence from the first hydraulic station (1) toward the steam turbine group (7).

5. The high temperature gas-cooled reactor steam bypass system according to claim 4, characterized in that: It also comprises a one-way check valve (11), wherein the one-way check valve (11) is arranged on the second fluid path (16), and the one-way check valve (11) is arranged between the second drive mechanism and the first hydraulic station (1).

6. The high temperature gas-cooled reactor steam bypass system according to any one of claims 1 to 5, characterized in that: It also includes a second branch (14), one end of which is in communication with the first branch (13), and the other end of which is connected to a second condensed gas inlet of the condenser (8).

7. The high temperature gas-cooled reactor steam bypass system according to claim 6, characterized in that: It also comprises a second bypass valve (5), wherein the second bypass valve (5) is arranged on the second branch (14).

8. The high temperature gas-cooled reactor steam bypass system according to claim 7, characterized in that: It also includes a third pressure maintaining mechanism (12) and a second hydraulic station (6), one end of the third pressure maintaining mechanism (12) is connected to the second bypass valve (5), and the other end of the third pressure maintaining mechanism (12) is connected to the second hydraulic station (6) via a third fluid path (17).

9. The high temperature gas-cooled reactor steam bypass system according to claim 8, characterized in that: It also includes a controller, which is respectively connected to the first hydraulic station (1), the second hydraulic station (6), the steam turbine unit (7), and the main steam valve unit (10).

10. A control method for a high temperature gas-cooled reactor steam bypass system, used for using the high temperature gas-cooled reactor steam bypass system according to claim 1, characterized in that: In a normal operating state, the steam turbine unit (7) operates normally, and the first bypass valve (4) is closed by the first pressure maintaining mechanism (3), so that the first bypass valve (4) isolates the first branch (13); in an abnormal state, the steam turbine unit (7) fails and shuts down, and the pressure in the main steam pipe (2) increases suddenly. The first pressure maintaining mechanism (3) opens the first bypass valve (4), so that the steam in the main steam pipe (2) enters the condenser (8) through the first branch (13).

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